While high quality petroleum reservoirs have been successfully explored and exploited for producing oil and gas, large reservoirs are increasingly difficult to find and many face the termination of primary recovery where large portions of the hydrocarbons remain trapped within the reservoir. In addition, many reservoirs lack sufficient natural forces to be produced by primary methods from the very beginning. Recognition of these facts has led to the development and use of many enhanced oil recovery (EOR) techniques. Some of these techniques involve injection of steam into the reservoir to force hydrocarbons towards and into a production well. While many reservoir simulators are based on an isothermal liquid model, the high temperature process of steam injection requires a thermal model to be included in the simulators where high temperature gradients and their impact on the system are modeled.